diff --git a/arch/arm/src/efm32/efm32_serial.c b/arch/arm/src/efm32/efm32_serial.c
index 133974d6f651..46df453799ae 100644
--- a/arch/arm/src/efm32/efm32_serial.c
+++ b/arch/arm/src/efm32/efm32_serial.c
@@ -755,7 +755,7 @@ static int efm32_rxinterrupt(int irq, void *context, void *arg)
  *
  ****************************************************************************/
 
-static int efm32_txinterrupt((int irq, void *context, void *arg)
+static int efm32_txinterrupt(int irq, void *context, void *arg)
 {
   struct uart_dev_s *dev = (struct uart_dev_s *)arg;
   struct efm32_usart_s *priv;
diff --git a/arch/arm/src/efm32/efm32_usbhost.c b/arch/arm/src/efm32/efm32_usbhost.c
index f87638abd282..74d6b9f4157e 100644
--- a/arch/arm/src/efm32/efm32_usbhost.c
+++ b/arch/arm/src/efm32/efm32_usbhost.c
@@ -1925,7 +1925,7 @@ static ssize_t efm32_in_transfer(FAR struct efm32_usbhost_s *priv, int chidx,
   chan->xfrd   = 0;
 
   start = clock_systimer();
-  while ((chan->xfrd < chan->buflen > 0)
+  while (chan->xfrd < chan->buflen)
     {
       /* Set up for the wait BEFORE starting the transfer */
 
diff --git a/arch/renesas/src/m16c/m16c_serial.c b/arch/renesas/src/m16c/m16c_serial.c
index 72cf64a3a5de..9b4a522f76f5 100644
--- a/arch/renesas/src/m16c/m16c_serial.c
+++ b/arch/renesas/src/m16c/m16c_serial.c
@@ -582,7 +582,7 @@ static int up_setup(struct uart_dev_s *dev)
   if (priv->uartno == 2)
     {
       regval  = getreg8(M16C_U2C1);
-      regval |= ((UART_C1_U2IRS|UART_C1_U2RRM);
+      regval |= (UART_C1_U2IRS|UART_C1_U2RRM);
       putreg8(regval, M16C_U2C1);
     }
   else